A conventional vehicle seat adopts a mechanism which instantaneously moves a headrest forward upon occurrence of a rearward collision of a vehicle in order to support a head of a seated occupant. Here, in a known example of the mechanism which moves the headrest forward as described above, there is utilized an operation cable adapted to be pulled upon receiving a backrest load applied to the seat back from the seated occupant at the time of occurrence of the rearward collision of the vehicle.
This operation cable extends from inside of the headrest through a headrest stay serving as a support rod of the headrest, and is arranged inside of the seat back. Thus, in the case in which the headrest is detachable with respect to the seat back, it is necessary, for example, to divide the operation cable into operation cable portions, separately to arrange the cable portions in the two components beforehand, and connect the end portions of the operation cable portions to each other when attaching the headrest.
In this connection, Japanese Laid-Open Patent Publication No. 2005-304565 discloses a technique in which there is arranged an ascent/descent mechanism which raises and lowers a headrest installed at the upper portion of a seat back to adjust the installation height thereof. According to this disclosure, there is arranged inside the seat back an ascent/descent body driven to be raised and lowered by using an electric motor as a drive source. And, a headrest stay is inserted into the ascent/descent body from the upper portion side of the seat back to be set therein, whereby the headrest is supported so as to be capable of ascending and descending with respect to the seat back.
Thus, there is a need in the art to firmly connect each of the respective connection end portions of the cable portions respectively arranged in the headrest and the seat back through the operation of inserting the headrest stay into the seat back to attach it to the ascent/descent body.